After many more hours of work, I found the problem was that Crystal is using the Sybase syntax (*= in the WHERE clause) to invoke a left outer join, rather than the SQL-92 standard of LEFT OUTER JOIN in the FROM clause. I posted a message on Crystal's forums, but haven't heard back yet.

BTW, I got it to work by manually editing the SQL syntax, but it took me a couple more hours to figure out the magic to edit the syntax AND get the subreport link to work. It's still a Crystal bug, tho, and I hope they fix it soon. I would rather not have to manually edit all my reports' SQL statements. It seems to me that direct OLE-DB is simpler than ADO and probably faster.

This is doubly annoying because they use the correct syntax for VFP's ODBC. That's how I figured out what was going wrong. CR "knows" something about which ODBC providers use which syntax for outer joins and I suspect something similar is going on with OLE-DB, but the information hasn't been programmed in yet for VFPOLEDB.